title: High prevalence of prolonged QT interval duration in male patients with Cushing's disease.
abstract: Hypogonadal males have recently been shown to present prolonged QT interval, an electrocardiographic measure indicative of risk for fatal cardiac arrhythmias. Excess cortisol secretion induces low testosterone levels in male patients with Cushing's disease but no study has yet evaluated if this is accompanied by changes in QT interval duration. We therefore decided to evaluate whether male patients with Cushing's disease present changes in QT interval duration. QT interval was measured in electrocardiographic readings from 19 men and 35 women with Cushing's disease and age- and sex-matched controls were used for comparison. QT interval was corrected for heart rate according to Bazett's formula (QTc) and QTc >440 msec and >460 msec were taken as indicative of increased risk for torsade de pointes in men and women, respectively. Mean QTc was significantly longer in male patients compared with healthy controls (426.9±9.27 vs. 389.7±8.31, p<0.05) and 5 men with Cushing's disease presented prolonged QTc (prevalence 26%). By comparison, none of the women with Cushing's disease presented prolonged QTc. Hypokalemia and low testosterone appeared associated with long QTc.
  
  
  CONCLUSIONS
  Male patients with Cushing's disease present prolongation of QT interval which may lead to measurements associated with high risk for ventricular arrhythmias. Both low testosterone levels and hypokalemia appear to contribute to long QT in men with Cushing's disease.
authors.affiliation: Chair of Endocrinology, University of Milan, Italy. fpg@auxologico.it
authors.forename: F
authors.initials: F
authors.lastname: Pecori Giraldi
authors.forename: P M
authors.initials: PM
authors.lastname: Toja
authors.forename: G
authors.initials: G
authors.lastname: Michailidis
authors.forename: A
authors.initials: A
authors.lastname: Metinidou
authors.forename: M
authors.initials: M
authors.lastname: De Martin
authors.forename: M
authors.initials: M
authors.lastname: Scacchi
authors.forename: M
authors.initials: M
authors.lastname: Stramba-Badiale
authors.forename: F
authors.initials: F
authors.lastname: Cavagnini
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D047748:Pituitary ACTH Hypersecretion / Q000150:complications / Q000503:physiopathology*; D015995:Prevalence; D012307:Risk Factors; D012727:Sex Characteristics